Earlier quoted context omitted.
There was a in-depth article from Vanity Fair from 2012, "Microsoft’s Lost Decade" which tries to put together what happened. http://www.vanityfair.com/news/business/2012/08/microsoft-lo... Some excerpts: By 2002 the by-product of bureaucracy—brutal corporate politics—had reared its head at Microsoft. And, current and former executives said, each year the intensity and destructiveness of the game playing grew worse a…
>no more using C# So what did they use instead? C++ ?
Yes, that's pretty much what the bulk of everything that comes with Windows is written in.